1. Field of the Invention
The present invention relates to an endoscope apparatus including an image pickup device and a signal processing circuit for the image pickup device.
2. Description of the Related Art
In recent years, endoscopes with an image pickup device mounted in a distal end of an insertion portion thereof have widely been used in the medical field and the industrial field. Also, the image pickup devices mounted in the endoscopes have the tendency of pixel count increase to have a large number of pixels.
As described above, an image pickup device with an increased number of pixels requires an increase in drive frequency of a horizontal transfer signal, etc., in image pickup drive signals for reading out information on an image picked up by the image pickup device, in order to maintain a same frame rate as that before the increase.
For example, as a first conventional example, Japanese Patent Publication No. 3312766 discloses an endoscope apparatus including a signal processing apparatus including a plurality of image pickup device drive circuits and a plurality of signal processing circuits corresponding to plural types of image pickup devices, in which an image pickup device drive circuit and a signal processing circuit corresponding to an image pickup device mounted in an endoscope connected to the signal processing apparatus are selected.
Also, as a second conventional example, Japanese Patent Publication No. 4608766 discloses that in a camera mounting in an image pickup device, a frame rate of the image pickup device is changed according to a detected brightness and a detected frequency of illumination.